http://articles.mercola.com/sites/articles/archive/2015/01/13/whooping-cough-bacteria-evolves.aspx?e_cid=20150113Z1_DNL_NonBuyer_art_1&utm_source=dnl&utm_medium=email&utm_content=art1&utm_campaign=20150113Z1-NonBuyer&et_cid=DM64763&et_rid=804018969

Evolving Bacteria Outsmarts Vaccines